Every morning in this parched wilderness in the remote north-east of Brazil, biologists cram into a tiny wooden hut hoping to glimpse a very special blue parrot.

When they hear the distinctive caws announcing the arrival of the Spix's macaw, they smile with relief. The elegant bird flies on to the tall caribeira tree and, after 20 minutes perched on a branch, slips into its nest in the tree's hollow trunk.

Each time he comes it's a great feeling . It's one more day of hope for the species, says Yara Barros, who has been observing the parrot daily for three years. The Spix's macaw has a regrettable claim to fame. He is the rarest bird in the world, the sole member of his species left in the wild. Due to the predatory habits of humans - which captured its numbers for private aviaries - this remaining male Spix's, which lives near Curaca, 1,300 miles north of Rio de Janeiro, is the last step before extinction.

His unique, exaggerated situation has made him an international cause celebre. He has become a worldwide symbol for nature conservation and of how international co-operation fights the forces of animal trafficking, now considered the third-largest illegal market after drugs and guns.

Few humans can boast the attention that the lonesome Spix's now receives. Four people, supported by an international organisation, are employed to observe him during daylight hours. Local people, most living in extreme poverty and many barely literate, keep notes of whenever they see the bird flying nearby.

"People always ask why do we have all of this just to save one bird, but it's a call to arms," says Barros, the field co-ordinator of the Spix's Macaw Project.

"It's an alert to the world about how close to extinction you can get. Man was responsible for the absurd situation of there just being one left. So there is a moral responsibility to save it. The Spix's is a figurehead."

Macaws are long-tailed members of the parrot family. Existing from Mexico to Argentina, they are an emblem of the American tropics - but their beauty has been their downfall. Thousands have been captured for private collectors. Of the 16 species left, nine are considered at risk. In the 1980s, naturalists assumed the Spix's had died out in the wild. Then, in 1990, a Brazilian farmer from near Curaca turned up with snaps of a bird, its long tail dark blue and its head a bluey-white.

The excitement in ornithological circles on the rediscovery was so great that the the Permanent Committee to Save the Spix's Macaw - set up the previous year to link the owners of the 15 birds in captivity spread over three continents - established a base camp in the Brazilian outback.

The hope is to use the Curaca Spix's to reintroduce gradually other Spix's to the wild. This male is the only one with the knowledge of how to survive, says Yara Barros.

He has memory of where there is food, of which cactus to sleep on. He knows all the places to find water. Work has concentrated on finding the male Spix's a family. Spix's, like all parrots, have one partner for life. Researchers located a female Spix's in Recife, 400 miles away, which had spent seven years in captivity. She was taken to Curaca, where the head biologist gave her a crash course in non-sedentary life, feeding her food from the wild and building up her wing muscles.

In March 1995, she was released. The female Spix's quickly started courting the male, but one day she s disappeared. A search party of 30 people failed to find any trace. A local cow-herder spotted the dead bird, probably the victim of an electrical wire, but was afraid to say, fearing the project would stop.

Researchers devised another tactic. When they discovered the Spix's in 1990, it was courting a macaw from the closest species, a green Illiger's macaw. The biologists decided to experiment with the cross-species couple.

A year ago, Barros swapped the infertile eggs that the Illiger's Spix's produced for wooden eggs for the period of incubation . When the eggs were due to break, she found a pair of new-born Illiger's chicks and put them in when the Illiger was out the nest.

"We were praying that she accepted them. When we had a peek in the nest the next day, it was full of food. In other words, she had accepted it. We discovered then that this couple has parenting skills," said Barros.

Last year's experiment has led Barros to hope the same would work with newborn Spix's chicks. The only problem is that all the reproducing Spix's couples are in the northern hemisphere - in Switzerland, Spain and the Philippines - and so the reproductive season is six months out of synch.

Next year, however, six Spix's are to be moved to an aviary near Curaca, including one couple, to try and induce them to produce young at the correct time.

The Spix's Macaw Project has not just helped birds. It has transformed the poor, sleepy town of Curaca by providing it with a primary school, renovating the town theatre and giving it a sense of pride. Children parade in the streets dressed as Spix's macaws.

"Without the support of the local population the project would never work. We rely on people to keep monitoring the bird when he is flying a long way from the nest," says Alexander Gomes, the field assistant.

Jorge de Sousa Rosa (42) has swapped his life as a herder to become a full-time birdwatcher. "I like sitting here all day," he says. "When I was a teenager I remember about 10 of them flying around here. I also remember the traffickers who came. We didn't realise how valuable the birds were."

Barros adds : "It's great that we have taught people that it is important to keep a species alive. The first time I saw him the first sensation I had was fear. You see how delicate the situation is, but, at the same time, he was first spotted nine years ago and he's still here. There is hope."